Unlike a backlit display having an internal light source (e.g. one or more light sources mounted inside the display), a reflective display utilizes an external light source (e.g. the sun, a room's overhead electric lighting, a table lamp, etc.) in order to illuminate the display. Ambient light emanating from the external light source(s) is reflected by the display back toward the display's user. Reflective displays are typically more efficient than backlit displays, in the sense that reflective displays do not consume power in order to energize an internal light source.
Reflective displays require ambient light in order to be visible and thus are not well suited to use in low ambient light (i.e. dim or dark) environments such as a home theatre, airplane, etc. Moreover, the illumination intensity (i.e. brightness) of a reflective display is limited by the intensity of the ambient light which is incident upon the display. In some situations it is desirable for the illumination intensity of a reflective display to exceed the illumination intensity of the ambient light incident on the display, for example to facilitate use of the display in a low ambient light environment. Such situations are addressed below.
The foregoing examples of the related art and limitations related thereto are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.